Junction connectors of the set screw bar type have been used for many years. Such connectors comprise extruded bodies of aluminum or copper-aluminum alloy for example, and which may be generally square in transverse section. One face is provided with two or more conductor receiving blind holes. A second face 90.degree. to such first face has corresponding and intersecting blind tapped holes which receive set screws usually having recessed hex heads. A conductor is inserted into a blind conductor receiving hole when the set screw is backed-off. The set screw is tightened down on the conductor to clamp it to the body or bar of aluminum. Other conductors are secured in the same way. The number of such connections may be from 2 to 8 or, even more. Such connectors are widely used for connections for power distribution from transformers.
In the past, many transformers were mounted on poles, and still are. However, much new electrical distribution today is underground. This includes not only the conductor but the transformer and the set screw connector. The connections are usually made below grade in a vault or fairly deep hole with confined space. Many such connections are made in mud or muddy water. If the connection is not below water initially, over its service life, it will be due to rains or floods or even normal seasonal fluctuations of ground water.
In order to provide such connectors with a longer serviceable life, submersible connectors have been developed. Such connectors are provided with a molded waterproof encasement. Problems, however, arise both where the conductors enter the case and more particularly where access to the set screw is required.
The case usually includes long projecting sleeves at the conductor ports which are plugged with elongated grommets which are termed rockets. The rockets include stepped tips which are out off at a selected step depending on the size of the conductor. The conductor is inserted through the cut-off tip of the rocket which now becomes an elongated sleeve grommet. Both are inserted into the long sleeve of the case with the grommet sealing against the interior of the sleeve and the projecting tip of the conductor extending beneath the path of the set screw. The preparation and insertion of the conductor usually requires at least two hands of a lineperson.
The access to the set screw is through a port provided by a somewhat shorter cylindrical sleeve projection. The port is provided with a removable cap or plug which is supposed to provide a watertight connection. When the plug is removed, access is provided to the recessed hex head set screw.
The submersible connection in each of the paired sleeve ports include the rocket and the watertight plug. When the connection is initially installed, only some of the paired ports may be used and additional connections may be made later, or even much later.
When a connection is made, the rocket is removed and the proper sleeve grommet is fashioned and inserted on the end of the conductor. Before inserting the conductor, the lineperson has to remove the plug on the corresponding set screw port sleeve projection and make sure the set screw is backed out. This is done by inserting a hex driver such as an Allen wrench and backing out the set screw. Only then is the conductor inserted to a position to be clamped by the set screw. Because of the tight connection of the plug in its sleeve, such plugs usually have to be removed with a pair of pliers. In fact, most such plugs are provided with a center projecting tab to enable them to be gripped by a pair of pliers. The set screw is then tightened with the hex driver and the electrical connection is made. While the grommet seals the conductor port, the cap has to be replaced and properly seated to maintain the waterproof integrity of the case. The lineperson has to perform all of the above steps usually with heavy gloves on, and in cramped dark, and wet space. It is not uncommon for the bottom of the space to be filled with muddy water.
While the lineperson may be wearing a tool belt, and can readily put down or pick up the tools, the lineperson has no place to put the plug. The plug is, in fact, often dropped, and often after the connection is made, the lineperson may wind up groping in the mud or water to retrieve the plug.
The problem is made worse by the fact that the material of the case and cap is usually rubber or an EDPM, which is black. This makes for an excellent camouflage. Some makers of submersible connectors paint the caps yellow, but they are still lost.
If the plug can not be found readily, the common practice is to cover the port hole with a strip or strips of electrical tape, which is a makeshift seal, if a seal at all. For many years, the major cause of failure of this type of connector is the loss of watertight caps and plugs. No plug or a makeshift plug allows water to penetrate the connector.
It would, therefore, be desirable to have a submersible electrical set screw connector which could more easily be used in the cramped and wet environment of an underground connection to a transformer. It would also be desirable to have such a connector where the caps or plugs could not get lost and would remain handy to the lineperson efficiently to complete a long lasting failure free set screw connection.